This invention relates to process and apparatus for forming hose cuffs, hose, particularly corrugated hose, provided with cuffs, hose cuffs and hose, particularly corrugated hose, provided with cuffs formed by such process. This invention further relates to apparatus and process for forming dual hose cuffs for being split to provide one hose cuff on one end of a length of corrugated hose and another hose cuff on another length of corrugated hose.
Typical prior art corrugated hose is shown in FIG. 1 and indicated by general numerical designation 10. The hose 10 is provided at its opposed ends with what are referred to in the art as cuffs, or hose cuffs, and which are identified in FIG. 1 by numerical designations 11 and 12. The corrugated hose 10, as further known to the art, is used to communicate various gases, such as for example, breathing gas to a patient and exhalation gas away from the patient, anesthesia gas to the patient, and the like. For such gas communication, as further known in the art, the hose cuffs 11 and 12 are for connecting the hose 10 to various connectors provided, for example, ventilation machines, anesthesia machines, the proximal end of an endotracheal tube, a face mask connector, and the like. The cuffs 11 and 12 fit over the connectors on such devices whose connectors typically are referred to in the art as male connectors. Since the hose cuffs fit over such male connectors, such hose cuffs are typically referred to as female connectors. Such male and female connectors, as further known to the art, engage in a sliding wedged, or slight interference fit, to provide a fluid-tight connection or fit. A diagrammatical example of such fluid-tight connection is shown in FIG. 2. An anesthesia machine 13, for example, is provided with an outwardly extending and inwardly tapered conical male connector 14 for fluid-tight connection with the female hose cuff 12 provided on the hose 10. Accordingly, it will be further understood that the hose cuff 12 for such connection is an outwardly tapered conical female hose cuff for the above-noted sliding wedge, or slight interference fit, to provide a secure and fluid-tight engagement or connection with the conical male connector 14. It will be understood that the conicalness of the female hose cuff 12 and the male connector 14 are standard tapers for the medical industry and are thus exaggerated in FIG. 2 for clarity of presentation and ease of understanding.
Typical prior art process and apparatus for continuously forming successive lengths or sections of corrugated hose or tubing separated by intermediate sections of dual cuffs are shown in FIG. 3; such successive sections of corrugated hose and intermediate dual cuffs are illustrated diagrammatically in FIG. 3 and identified by general numerical designation 15. The hose and dual cuffs 15 include representative sections or lengths of corrugated hose 16a, 16b and 16c separated by intermediate dual cuffs 18a and 18b. The apparatus illustrated in FIG. 3 includes an extruder 19 for continuously extruding a hollow tube of deformable material 20 between opposed elliptical trains of forming blocks identified respectively by general numerical designations 21 and 22.
As indicated diagrammatically in FIG. 4, the dual cuffs 18a and 18b are dual cuffs in the sense that after forming they cut transversely through their middle to provide two cuffs. Dual cuff 18a, upon being cut transversely through its middle, provides one hose cuff on an end of the corrugated hose 16a and another hose cuff on one end of the corrugated hose 16b, and, dual cuff 18b upon being cut transversely through its middle, provides one hose cuff on one end of the end of corrugated hose 16b and one hose cuff on one end of the end of corrugated hose 16c. 
Referring again to FIG. 3, the trains of deforming blocks 21 and 22 include pairs of corrugation blocks for forming the lengths or section of corrugated hose 16a–16c and pairs of dual cuff blocks for forming the dual cuffs 18a and 18b. As is further known, the trains 21 and 22 bring these blocks into pairs of opposed and engaged blocks as indicated diagrammatically in FIG. 3 by the representative pair of opposed and engaged corrugation blocks 24a and 24b and by representative pairs of engaged and opposed dual cuff blocks 26a and 26b. As illustrated diagrammatically in FIG. 5, with regard to representative opposed pairs of corrugation forming blocks 24a and 24b, upon being placed into opposed engagement by the trains 21 and 22 (FIG. 3), the internal corrugation forming surfaces of these blocks form a generally cylindrical, although irregularly shaped due to the internal corrugation forming surfaces, cylindrical corrugation forming chamber indicated diagrammatically in FIG. 5 by numerical designation 24c. 
The trains of corrugation and cuff forming blocks 21 and 22 shown in FIG. 3 may be generally of the type described and shown in FIGS. 5 and 6 of U.S. Pat. No. 5,996,639 which is hereby incorporated herein by reference as if fully reproduced herein and the trains of blocks described and disclosed in U.S. Pat. No. 3,286,305 which is hereby incorporated herein by reference as if fully reproduced herein. In FIG. 5 of incorporated U.S. Pat. No. 5,996,639, blow molding apparatus is shown for forming corrugated tubing or hose and in FIG. 6 vacuum assisted blow molding apparatus is shown. Referring again to FIG. 3, it will be understood that in the prior art process illustrated the lengths or sections of corrugated tubing or hose and dual cuffs are formed by vacuum assisted blow molding wherein pressurized air is supplied to the interior of the tubing 20 by the air pressure nozzle 19a shown in FIG. 3 to assist the vacuum provided through the block vacuum lines provided in the forming blocks as shown in detail in FIGS. 6 and 7 and described below.
With further regard to the corrugation blocks, a representative opposed pair of corrugation blocks 24a and 24b are shown partially and diagrammatically in enlarged cross-section in FIG. 6. The deformable tubing 20 is fed forwardly as indicated by the arrow in FIG. 6 between the corrugation blocks 24a and 24b, pressurized air is forced into the interior of the material 20 from the pressurized air nozzle 19a (FIG. 3), and vacuum is drawn against the tubing through the vacuum lines 27—27 to expand the tube 20 radially outwardly so as to force the tube 20 into engagement with the corrugated forming surfaces 24c and 24d of the corrugation blocks 24a and 24b to form, as indicated diagrammatically, the corrugated section or length of corrugating hose 16b. 
As noted above with regard to FIGS. 1 and 2, the cuffs 11 and 12 are conical female cuffs tapering outwardly as indicated diagrammatically by the exaggerated conicalness of the cuff 12 as shown in FIG. 2. Accordingly, it will be understood that in the prior art the opposed pair of dual cuff forming blocks 26a and 26b, illustrated diagrammatically in cross-section and enlarged partial view in FIG. 7, are provided with opposed dual cuff forming surfaces 28a and 28b. The deformable tube 20 is fed forwardly, typically at a constant rate, between the dual cuff forming blocks 26a and 26b and vacuum is drawn in the vacuum lines 29—29 to force a section of the deformable tube 20 radially outwardly and into engagement with the cuff forming surfaces 28a and 28b to form the dual cuff 18b. 
As is further known to those skilled in the art, at present, hose cuffs and mating connectors are increasingly designed for compliance with International Standards Organization (ISO) standards for such hose cuffs and connectors whereby the conical male connector will have an outer diameter and the female hose cuff will have an inner diameter of 22 mm and a taper angle stated in three places as 0.716° taper per side which is a taper of one inch over a length of 40 inches. It will be understood that even though such male connectors and female cuffs are tapered and are therefore conical, and in actuality due to such conicalness have slightly varying inner and outer diameters along their length due to such slight taper, less than 1° taper per side, such ISO diameters are referred to in the art as the above-noted 22 mm diameters.
Shown in FIG. 8 is a length of corrugated hose 30 provided with a hose cuff 32 conforming to the above-noted ISO standards. That is, the hose cuff 32 has an inner diameter D1 of 22 mm and a taper angle A of approximately 0.716°. The corrugated hose section of axial length 30 is an outer diameter D2, an inner diameter D3, and an average diameter of D4. As further known to those skilled in the art, to prevent air flow constrictions at the hose cuff, or the connection provided by the hose cuff, the hose cuff diameter D1 is larger than the average diameter D4 of the corrugated hose 30. With further regard to FIG. 8, it will be understood that the conicalness of the hose cuff 32 is exaggerated merely for purposes of clarity of understanding.
Desirably, in connection with satisfying the above-noted ISO standards, the above-noted prior art process and apparatus shown in FIG. 3 for forming corrugated hose and dual cuffs would provide dual cuffs which, upon being split through their middle as shown in FIG. 4, would provide two hose cuffs which would conform to the ISO standards, namely, each such hose cuff would have an inner diameter of 22 mm and a total taper angle of 1.43°, or would deform to fit such a connector.
In the prior art, and as illustrated generally in FIG. 9, the dual cuffs are formed by symmetrical dual cuff forming blocks such as the symmetrical dual cuff forming blocks 36 and 38. Such symmetrical dual cuff forming blocks provide a dual cuff forming chamber 39 having a leading diameter D6, a trailing diameter D7 and a middle diameter D8. The leading diameter D6 and the trailing diameter D7 are leading and trailing diameters in the sense of the direction of hose cuff, and of course corrugated hose, forming as indicated by the arrows in FIG. 9. The dual cuff forming blocks 36 and 38 are symmetrical dual cuff forming blocks in the sense that the leading diameter D6 and the trailing diameter D7 are equal and are equally spaced from the middle diameter D8. Again, it will be understood, in FIG. 9, that the conicalness of the dual cuff forming chamber 38 is exaggerated for clarity of presentation and understanding. The diameters D6, D7 and D8 may also be referred to as the diameters of the dual cuff forming blocks 36 and 38.
It has been found, typically, that upon the symmetrical dual cuff forming blocks 36 and 38 of FIG. 9 being designed to form cuffs satisfying ISO standards, that such dual cuffs upon being split do not provide two dual cuffs each of which conforms to the above-noted ISO standards, but instead, such symmetrical dual cuff forming blocks typically provide dual cuffs which upon being split form two hose cuffs neither of which conforms to the noted ISO standards. This is because it has been found that even though such dual cuff forming blocks 36 and 38 are designed to form dual hose cuffs conforming to the ISO standards, as the dual cuffs are formed using such symmetrical cuff forming blocks, the dual cuffs begin with a narrow thickness which increases in thickness gradually but continuously as the dual cuffs are being formed and which thickness increases in thickness in the direction opposite to the direction in which such dual cuffs are being formed. This is illustrated diagrammatically in FIG. 10 by the two hose cuffs 40 and 41 formed, typically, by such symmetrical dual cuff forming blocks. It has been found, typically, that due to such increase in thickness, that the first hose cuff 40 formed (FIG. 10) will have an inner diameter D10 larger than 22 mm and a taper angle 18 larger than 0.716°. Hence, the hose cuff 40 will be too large to engage an ISO tapered male connector in an air-tight fit. The second formed hose cuff 41 will have an inner diameter D11 smaller than 22 mm and a taper angle A3 smaller than 0.716° and hence will provide a hose cuff too small to engage an ISO tapered male connector in an air-tight fit. It is believed that the reason for the increase in thickness and forming of such two non-conforming hose cuffs is illustrated in FIGS. 11–14. It will be further understood with regard to the sequential dual cuff and corrugated tube forming illustrated in FIGS. 11–14 that such is in the context of using the symmetrical cuff forming blocks 36 and 38 of FIG. 9 designed to provide dual cuffs which upon being split transversely through the central apex were intended to provide two hose cuffs which conform to the above-noted ISO standards, namely, each hose cuff having an inner diameter of 22 mm and a taper angle of 0.716° per side, so that such hose cuffs can engage ISO tapered male fittings in a fluid-tight and mechanically secure engagement.
Referring to FIG. 11, a hollow tube of deformable material 42 is being advanced at a constant rate in the direction of the arrows and opposed pairs of corrugation blocks, 43 and 44 and 45 and 46, have engaged a portion of the tube 42 and formed a first section or length of corrugated hose 48, the pairs of dual cuff forming blocks 36 and 38 (FIG. 9) have not yet engaged the tube 42. Referring further to FIG. 13, it will be understood that the first formed hose cuff 50 and the second formed hose cuff 52 combine to form a dual hose cuff indicated by general numerical designation 53. It will be further noted from FIG. 13 that the dual hose cuff 53 increases in thickness in a direction opposite to the direction of forming indicated by the arrows in FIG. 13.
As shown in FIG. 12, the symmetrical cuff forming blocks 36 and 38 have begun to engage the tube of formable material 42, advancing at a constant rate, and have formed what will become a first hose cuff 50. As noted above with regard to FIG. 8, to prevent gas flow constriction, the inner diameter D1 of the hose cuff 32 (FIG. 8) is larger than the average diameter D4 of the corrugated hose or tubing 30 (FIG. 8) and hence to begin to form such hose cuff 50 of FIG. 12, the tube 42 must expand further radially outward than is required to form the corrugated hose 48 of FIG. 12. Hence, it will be understood that, in essence, as the hose cuff 50 of FIG. 12 begins to be formed there will be, momentarily, a lack of sufficient tube material 42 to expand radially outwardly at the thickness of the corrugated hose or tubing 48 and hence the beginning of the forming of the hose cuff 50 it will have a thickness narrower than the thickness of the corrugated tubing 48 but which thickness will increase gradually, as shown in FIG. 12, toward the central apex C of the dual cuff to be formed. As the hose cuff 50 is being formed, the material of the tube 42 advancing at a constant rate, in essence “catches up” with the radial outward expansion material demand required to form the hose cuff 50. This phenomenon occurs as extrusion speeds increase relative to the melt flow of the parison.
Referring to FIG. 13, the opposed pair of dual cuff forming blocks 36 and 38 have further engaged the advancing tube 42 and have formed the second hose cuff 52 of the dual hose cuff formed. It will be noted, as the material of the tube 42 continues, in essence, “to catch up,” the thickness of the second formed hose cuff 52 continues to increase in thickness from the circular apex C back toward the direction in which the tube 42 is advancing and, as illustrated in FIG. 13, concludes with the formation of the second to be formed hose cuff 52 with an end thickness equal to, or at least substantially equal to, the thickness of the tube 42.
As further illustrated in FIG. 14, the forming process continues and the pair of opposed corrugation cuff forming blocks 54 and 55 engage a portion of the tube 42 and form a second section or length of corrugated hose 58. It will be understood, from FIG. 14, that the dual cuff including the first formed hose cuff 50 and the second formed hose cuff 52 will be of the type shown in FIG. 10 and described above, namely, the first formed hose cuff 50 will have an inner diameter and a taper angle generally the same as the hose cuff 40 shown in FIG. 10 or an inner diameter that is too large and a taper angle different than an ISO tapered male fitting causing a loose connection. Similarly, the second formed hose cuff 52 will be of the type of the hose cuff 41 shown in FIG. 10, namely, the second formed hose cuff 52 will have an inner diameter and a taper angle different than ISO standards and hence will not easily engage a tapered male ISO fitting in a fluid-tight engagement.